Finding Your Forum

This is basically a three-step process, and if you try to keep yourself focused on one part of the phase instead of jumping between phases, you’re going to stay on track a lot better.
During the first phase, you will be using a couple of different ways to find potential forums. When you’ve found a list of forums, you’ll visit them in the second phase. After you’ve visited the forums and checked their quality against the required criteria, you’ll evaluate each forum’s potential marketability in the third phase.
Researching Potential Forums

You’re going to use two different resources for this phase: forum directories and search engines. You can then take that information and see how it ranks in Alexa to determine the forum with the most traffic, among other things.
Big-Boards.com
A forum directory lists a lot of different forums that can be sorted by popularity, number of members, total posts, posts made recently, and a whole lot more. One of the most widely known forum directories is big-boards.com.
This site looks like it was thrown together in a night, and it probably was, but it’s an all-in-one site for people who are looking for new forums to haunt. This is a good place to start but it isn’t necessarily the best source of information – if it was then I’d tell you to just use this.
First, it’s outdated. But, being outdated is good because then you can get a snapshot of age. If the forum was popular when the site was current, and it’s still somewhat popular, then you’ve probably got a good forum.
Using the Search Engines
When you’ve compiled a decent list of forums, you’ll put that list aside temporarily and then start using the search engines to find more. When using the search engine, you want to search for two particular types of phrases:
•    “keyword or keyword phrase” forum
•    “keyword or keyword phrase” message board
Put some of the more popular keywords for your particular niche inside the quotes and remember to search with quotes since you want an exact match for your search.
You don’t have to get too extensive since you want the easiest to find forums instead of those that have used SEO extensively to get themselves listed higher in the rankings.
When you’re satisfied with your preliminary list of forums that you want to try, go to Alexa.com and do a search for each. You’ll be able to get their current traffic statistics as well as their rank on the web.
If the site was listed as a popular site on big-boards.com and is still popular on Alexa.com, then it’s probably a forum you should put at the top of your list.